Can I get some help with the back brakes?

[skylarmav1]

So I looked through the little pad and was able to see my rear roters.I thought it was time to attempt a rear brake pad replacement.

Basically, everything went fine. When I tried to push the pistons at both ends to fit the new pads, I was unable to push both simultaneously. I had to bleed some of the brake fluid from the rear speed bleed nozzle to reduce the pressure to push in both pistons in order to fit both pads. I then tried to reverse bleed the lines so I could force any air bubbles up to the top and make sure I had clean and full lines.

Now I have a problem. I have no pressure in the line. It is not leaking anywhere and I'm not feeling air escape. It just seems there is no pressure-before hand, all compnents worked fine -am I missing something? I have also pumped the rear brake lever at least 30 times in a row (after tighening everything up) to try to build up pressure-FYI. Should I have (during brake pad installation) hold brake lever down somewhere in the process? Thanks in advance for your help all.

Blue Beakster thanks you too!

Skylarmav1

[gregor]

If you have ABS and everything is assembled, turn on the ignition and then use the brakes. Beyond that I know no more.

[skylarmav1]

Thanks Gregor. This is a non ABS 02 model.

[kirby]

So I looked through the little pad and was able to see my rear roters.I thought it was time to attempt a rear brake pad replacement.

Basically, everything went fine. When I tried to push the pistons at both ends to fit the new pads, I was unable to push both simultaneously. I had to bleed some of the brake fluid from the rear speed bleed nozzle to reduce the pressure to push in both pistons in order to fit both pads. I then tried to reverse bleed the lines so I could force any air bubbles up to the top and make sure I had clean and full lines.

Now I have a problem. I have no pressure in the line. It is not leaking anywhere and I'm not feeling air escape. It just seems there is no pressure-before hand, all compnents worked fine -am I missing something? I have also pumped the rear brake lever at least 30 times in a row (after tighening everything up) to try to build up pressure-FYI. Should I have (during brake pad installation) hold brake lever down somewhere in the process? Thanks in advance for your help all.

Blue Beakster thanks you too!

Skylarmav1

Hi trying to figure what you mean about "reverse bleeding" exactly???

[AZBMWRIDER]

If you pushed the pistons in, you need to push the rear brake pedal a few times to get the piston back up against the pads, then you should have a functioning rear brake .

[skylarmav1]

Reverse bleed to use a syringe with tube attached to the back speed bleed to insert brake fluid there to push air bubbles out of the top of resevoir then tighten nut. My understanding is that the bubbles like to float up so it makes it easier and better chance of eliminating them.

[kirby]

Reverse bleed to use a syringe with tube attached to the back speed bleed to insert brake fluid there to push air bubbles out of the top of resevoir then tighten nut. My understanding is that the bubbles like to float up so it makes it easier and better chance of eliminating them.

OK just making sure we are on the same page.

The way it can be done that works (ABS may be different??)
Open the reservoir(rear) and top the fluid , then with the caliper installed and tight, open the bleeder and pump the rear brake pedal until you get a good flow. When this happens hold the pedal in the full down position and close the bleeder. re fill the reservoir to the proper amount and pump the read pedal until it is hard. Close everything up.
This is a short system(lines) and does not really require pumping fluid from the rear caliper to the reservoir 99% of the time since you have not really completely dismantled the system.

BTW the disc or the caliper on the rear do not float, and I never seen a floating caliper.

[skylarmav1]

Ok, so with all my manuals, and the internet, I couldn't have done it without this BMW posse. For some reason, I was forgetting the basics of Brake Bleading 101. I have done bikes, and a half a dozen cars and until Kerby gave me a quick refresher, I just had my head on backwards. Thanks all. Rear brakes work great! Another reason this site rocks over all others-the people, thx all who helped!

[skylarmav1]

I guess I could spell Kirby right :-)

[kirby]

I guess I could spell Kirby right :-)

More than happy to help!!

:-)

[gregor]

Phil Hawksley's BMW site gives the following spec. for the brakes.

Twin disc 305 mm / 12 in floating, 4 piston fixed calipers. From 200?: EVO brake system with dual disc, floating brake discs, diameter 320 mm / 12.6 in, 4 piston fixed caliper
Brakes, Rear
Single disc brake 276 mm / 10.86 in diameter, double piston floating caliper
ABS
Special equipment BMW Motorrad Integral ABS (partially integral)

The discs and rear calliper does float. Think about it- on the rear there are two pistons on one side, if the calliper did not float there would be no braking effort on the other side. The front callipers have pistons on both sides so no reason for callipers to move.

[kirby]

Semantics, on this side of the pond we call calipers that move "sliding or pin slide" calipers not floaters. At any rate they do a very bad job of sliding.

My Rockster has the 1100S rear no ABS. You can actually move floating discs that function/maintained properly but the rear caliper is ridged and they usually ware uneven.

I might add that my Guzzi has ridged front discs and completely ridged calipers. The drill is you have to shim the calipers to the mount to center them on the discs. Since hyd pressure is equal on both sides they will ware almost exactly the same. Of course this requires pistons on both sides to work well but my rear may as well be that way(ridged) as they don't slide very well.

I have only replaced the BMW rear pads one time in 200K miles and they were very uneven in ware.

[gregor]

Floating calipers seem to be the most common description (see below) and they have the characteristics of uneven pad wear that I remember from the 1960 and 1970s when I owned several less than wonderful British cars.
My BIL owns a Le Mans Mk1 and a Commando 850 and I will speak to him on disc brake maintenance in his experience.
Those ridged discs and calipers? Is that by design or defect?


By John Cagney Nash
eHow Contributor

A thorough understanding of sliding brake function is necessary for DIY repair.

Sliding brakes are properly known as floating brake calipers. The term “caliper” describes the assembly that houses the brake pads and the pistons which actuate them. Floating brake calipers comprise only one piston or pair of pistons; fixed calipers have two or more single pistons or pairs. The floating design is by far the most common type of braking actuator.
Read more : http://www.ehow.com/info_12217321_slidi ... -work.html

[kirby]

Floating calipers seem to be the most common description (see below) and they have the characteristics of uneven pad wear that I remember from the 1960 and 1970s when I owned several less than wonderful British cars.
My BIL owns a Le Mans Mk1 and a Commando 850 and I will speak to him on disc brake maintenance in his experience.
Those ridged discs and calipers? Is that by design or defect?


By John Cagney Nash
eHow Contributor

A thorough understanding of sliding brake function is necessary for DIY repair.

Sliding brakes are properly known as floating brake calipers. The term “caliper” describes the assembly that houses the brake pads and the pistons which actuate them. Floating brake calipers comprise only one piston or pair of pistons; fixed calipers have two or more single pistons or pairs. The floating design is by far the most common type of braking actuator.
Read more : http://www.ehow.com/info_12217321_slidi ... -work.html

Typical Moto Guzzi CHEAP!!! Its is by far the cheapest way to do it!!(bang for the buck, and they work very well Brembo no less).

I guess I call them sliders or pin sliders, until the pads go they work ok for public roads. Even my '97 VFR has 'em on the front.

Cheers

[gregor]

I now understand you meant rigid. I'm too literal and was thinking of 'ridged' and grooved through wear. I've experienced both sticking calipers and sticking/leaking pistons in cars over many decades. The materials chosen were wrong IMHO but- no doubt for road use- were built down to a price.

[peels]

I have only replaced the BMW rear pads one time in 200K miles and they were very uneven in ware.

200K!!!!!?


whut?!

were they made of Unobtanium?

[kirby]

70% cross country loaded. Reg maint and be smooth.

:-)

[peels]

70% cross country loaded. Reg maint and be smooth.

:-)

NICE. I half expected you to say that was a typo, and meant 20k, not 200... but...

Well see how it goes now, that last pair I Put on before working on the brakes didn't even make it to 3000. Should be better, but I don't expect to see that many miles. A: that would take me 20+ years at this pace. B: I am a heavy rear brake user.